(Reuters) - Voters from Mexico's ruling conservative party looked set to back their first woman presidential candidate on Sunday, early primary results showed, setting her up for a battle against the opposition front-runner.

Newspaper Reforma said with 42 percent of supporters' votes counted, former Education Minister Josefina Vazquez Mota had 58 percent of the vote compared to runner-up Ernesto Cordero's 32 percent in the National Action Party (PAN) primary. Televisa's leading newscaster cited similar numbers from Vazquez Mota's team, which could not immediately confirm the numbers.

To avoid a second round vote on Feb. 19, one candidate either has to win more than 50 percent of the votes or have at least 37 percent and a 5 percentage point lead over the runner-up.

If confirmed, the win will pit Vazquez Mota against telegenic Enrique Pena Nieto from the Institutional Revolutionary Party (PRI), which ruled Mexico for most of the last century, in a July vote.

National opinion polls show Vasquez Mota as the PAN's best chance against Pena Nieto, but she still trails him by around 20 percentage points.

Cordero, a former finance minister, was seen as the favorite of President Felipe Calderon.

(Reporting by Michael O'Boyle and Miguel Angel Gutierrez; Editing by Stacey Joyce)